The following is Part 2 of our three-part series showcasing the difference between running with power or with pace. See Part 1 and Part 3 here. These excerpts come from Jim Vance’s book Run With Power.
Windy, hot, or cold conditions can also affect pace negatively or positively, adding to the challenge of quantifying the intensity. Let’s say you are running on flat terrain on a windy day and your goal for today’s workout is to run hard intervals. To hold your prescribed interval times, you might feel as if you’re working much harder than on a calm day because of the wind. And you’d be right, but your pace wouldn’t show it because you held your times.
Pace Measures Speed, Not Intensity
The truth is that pace measures time and distance. Using pace is just like using a stopwatch that knows how far you’ve run and which does the speed calculation for you. Pace measures speed, but as you can see from the hill example, speed does not necessarily equal effort.
Why Does It Matter?
All of these tools are helpful in creating a snapshot to measure fitness, and yet none of them give us an impartial way to monitor training intensity with repeatable precision.
But when we measure stress incorrectly, our training suffers:
- We become more vulnerable to injury.
- We may not recover enough between workouts (or vice versa).
- We may do a workout at the wrong intensity and get the wrong adaptations from it (or no adaptations).
Any one of those setbacks can derail your training.
How Is Power Better?
What we need, clearly, is a better way to measure the stress we are inflicting in our daily training routines. And that’s exactly what the power meter provides, and it is why the power meter has the potential to revolutionize your run training.
In its simplest form, a power meter measures the force your feet put into the ground. That’s it.
A running power meter measures exactly how hard you are working and nothing else. It ignores all other variables. A power meter doesn’t care how much sleep you got last night, how much coffee you drank this morning, how hot it is outside, how steep the hill is, if it’s windy or calm.
Your power meter only sees one thing: how much power you’re putting out.
Your power meter directly measures the work you are doing during your workout. No other metric or tool can do that. All those other measurement tools just approximate our level of effort. Power eliminates the guesswork.
Since the research shows that working out at certain levels of effort causes specific changes that make us fitter, being able to accurately measure our workouts means we can be more precise in our training. Power meters can make every workout count more.
With a power meter, no longer will you wonder whether you are meeting the intensity, recovery, pace, and volume goals of your training plan. Instead, you will erase any doubts about your training, and you will be able to monitor changes and improvements in every aspect of your running fitness.
Power Is King of the Hill
Let’s head back to the hill for a workout with pace and then with a power meter. You’ll run normally this time, running a little harder up the hill and a little easier down the other side. Your GPS watch pace will show 10:00 min/mile heading up, 9:00 min/mile at the crest, and 8:00 min/mile heading down. From the perspective of your GPS watch, it will seem as if you slowed down, sped up, then sped up even more. Your pace will make it seem as if you were doing less work, more work, and then even more work, although the opposite is true.
What will your power meter show? Within a few steps into the hill, your wattage number will rise and plateau, showing you how hard you’re working as you head uphill. As soon as you hit the crest of the hill, your power will drop, then as you begin descending the hill, it will drop some more until it levels off at a lower wattage number. As you hit level ground, it will rise somewhat and level off at this new normal power output.
Your power meter will show you how hard you are working in real time. Since the goal of training is to exercise at specific levels to cause specific changes, only the power meter can accurately measure your effort on this hill and show you if you hit the right levels.